Abstract

Antibacterial activity of several local seaweeds has been screened. Most of these seaweeds species show
antibacterial properties against pathogenic bacteria from species of Vibrio and Pseudomonas. The activity of
seaweeds extracts were determined by type of solvent used in extraction. Respond of each pathogenic bacteria were
also different to each type of extract. Most seaweeds show stronger activity against Pseudomonas rather than Vibrio.
Caulerpa and Padina were more active against Pseudomonas compared to Sargassum and Gelidium. Compared to
other seaweeds, Sargassum and Gelidium were more active against Vibrio. It is predicted that Sargassum is the the
most suitable to be used in polyculture with tiger shrimp (Peneaus monodon), as this is the most active against the
most dangerous pathogenic bacteria, Vibrio harveyi. Beside that, the active component of Sargassum is solved in
water, therefore will be easier to diffuse into shrimp pond.